


Senku's X-Rated Travel Adventures

by JayTDawgzone9999



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Accidental Plot, Alternate Universe, Alternate Universe - Canon Divergence, Alternate Universe - Gender Changes, Blow Jobs, F/F, F/M, First Kiss, Gender or Sex Swap, Genderbending, Gentle Kissing, Kissing, Late at Night, Loss of Virginity, Multi, Multiple Orgasms, Oral Sex, POV Multiple, Senku is a girl but everyone else is the same gender as in canon, Shameless Smut, Size Difference, Smut, Some Humor, Threesome, Threesome - F/F/M, Vaginal Fingering, gender bend, gender swap
Language: English
Status: Completed
Published: 2020-06-20
Updated: 2020-06-20
Packaged: 2021-03-04 00:34:31
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,971
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24814645
Author URL: https://archiveofourown.org/users/JayTDawgzone9999/pseuds/JayTDawgzone9999
Summary: A/U where Senku, who's a girl,  finds that traveling halfway around the world can lead to some pretty unexpected adventures.
Relationships: Ishigami Senkuu/Kohaku, Kohaku/Mozu (Dr. STONE), Kohaku/Mozu (Dr. STONE)/Ishigami Senku, Mozu (Dr. STONE)/Ishigami Senku, Ogawa Yuzuriha/Ooki Taiju
Comments: 2
Kudos: 10





	Senku's X-Rated Travel Adventures

**Author's Note:**

> This was inspired by the following piece of fanart I found on twitter: https://twitter.com/drmikekun/status/1271801675108368386
> 
> Because if anyone would fill the Dr. Stone tag with weird filthy porn because of a piece of fanart, who else would it be besides me, that's why.

The crisp, salty scent of the ocean spray filled Senku's nostrils as she stood on deck, listening to Ryuusui shout with joy as the coastline of the North American continent appeared on the horizon and several other people cheered alongside the eccentric captain. One moment, Senku was standing there, enjoying the feeling of the cool breeze kissing her face, the next, she was screaming at the top of her lungs as Kohaku picked her up and leapt off of the Perseus shouting at the top of her lungs. 

"We made it, Senku! We're finally here, I can't believe it!" 

Senku could hardly move while Kohaku squeezed her, finding herself unable to speak until the taller girl set her down, ruffling her white and green hair with one hand. 

"This America place is gonna be a whole lot of fun to explore, I can just feel it!" Kohaku announced with confidence in her voice as Senku was just relieved to finally be standing on dry land. 

When the hunting team, (which Kohaku was a part of,) dashed off in pursuit of the horde of alligators that had just shown up, Kohaku assured Senku that she would let her eat the best parts of the alligator she killed. Stone Age people had their own way of doing things, Senku realized, appreciating Kohaku's thoughtful gesture. Before meeting Kohaku, Taiju and Yuzuriha were Senku's only friends, and ever since Senku met the citizens of Ishigami Village, Senku was all too glad to realize that most Stone Age people were just as kind, thoughtful, and curious about the world around them as most modern people. 

Finding a comfortable place to sit while waiting for the hunting team to return, Senku marveled at the beauty of her surroundings-America was truly a wonderful place, she thought, admiring the bright blue sky with puffy white clouds, the cool, refreshing air, the color of the beautiful wildflowers dotting the lush landscape. As eager as she was to bring back the modern world, Senku was glad nature had remained so beautiful-that the passage of time had done nothing to damage or ruin the world for the plants and animals that survived the fall of modern human civilization. 

______

"Wow, these are really tasty, I never knew alligators could taste so good!" Taiju commented before taking another large bite of one of the alligator burgers Francois made everyone. 

"They're pretty good." Yuzuriha agreed while Taiju eyed Senku's half finished burger with a longing look. 

"Hey, Senku, you gonna finish that?" 

"Taiju, don't rush her, you know Senku's a slow eater." Yuzuriha gently admonished him. 

"It's fine, I'm pretty full actually-I don't do much physical labor so I don't work up that much of an appetite." 

Senku's mouth turned up in a small, knowing smile as Taiju gratefully accepted the other half of her burger, happily munching away while Yuzuriha drank some water. When the two of them finished and awkwardly excused themselves to spend some time alone together, Senku chuckled softly to herself, assuring them both that she didn't mind. Sex wasn't something of any particular interest to her, but she couldn't help but find it amusing how easily Taiju and Yuzuriha still got all flustered around each other sometimes even after knowing each other for thousands of years (technically speaking.) Humans sure are a weird species, Senku thought, and that's why she liked people and wanted to bring back as many of them as possible. The more, the merrier (or, that is, the better for re-starting modern civilization and allowing everyone to thrive fulfilling their true potential.) 

Despite being something of a loner and an introvert, it warmed Senku's heart to see everyone-or almost everyone, at least, happy and laughing and enjoying their dinner, the setting sun painting the evening sky a gorgeous array of pink and orange hues. With Taiju and Yuzuriha gone (most likely back in their own tent,) Senku contemplated heading back to the tent she was sharing with Kohaku, at least until the other girl sat down next to her, wrapping her arm around her shoulder. 

"Hey, Senku, you want to take a walk and do some exploring? I know we're not going anywhere until tomorrow, so I wanna see if there's anything interesting around here while we're still here." 

Senku was a woman of many traits, and one of those, she found out, happened to be being unable to say no to Kohaku-she was loud, to be sure, sort of like Taiju, and like it was with Taiju, Senku found it endearing rather than annoying, and as time went on and their friendship grew, Senku appreciated Kohaku's energy and enthusiasm for life. 

______

"I can carry you by giving you a piggyback ride if you're tired." Kohaku reassured Senku after the two of them walked around for a while.

"Thanks, but I'm fine, really." Senku insisted, pausing to take a breather by sitting down on a large, flat rock. 

"Wow, it's really nice out here." Kohaku, whose gaze was directed at the full moon in the sky, mused. "The sky here's so pretty at night." 

"It is." Senku agreed, deciding to get up just then. While her spirit was willing, her body was tired and she fell over without warning. 

"Yeah, it-Oh my God, Senku!" 

"I'm telling you, I'm fine, I'm just a little tired-" Senku insisted as Kohaku grabbed her, both of them freezing for a moment when they heard someone else's voice. 

"So this is where you've been. Guess I'm not the only one who wanted to take a late night stroll, it seems." 

Kohaku and Senku turned to face the unexpected third party, Mozu-Kohaku still holding Senku as they both got a good look at him. 

"Oh, it's you again, why does that not surprise me?" Kohaku may or may not have rolled her eyes, but either way, it wasn't like Senku could tell. 

Senku considered asking Kohaku to put her down but found that she had forgotten how to speak when Mozu's eyes wandered over both of them while he replied. 

"And what's that supposed to mean? And here I thought we were friends." Mozu put on a fake disappointed look after scanning Kohaku and Senku with a level of enthusiasm anyone with brain cells could detect. 

I can't feel my arms anymore...Senku thought, as Kohaku had picked her up by the arms when she fell, holding Senku with both hands while the smaller girl had her arms straight down by either side like a particularly stiff-looking statue. 

"Well, that depends. I wouldn't mind hanging out with you more if you didn't run your mouth spouting off dumb comments as often as you do." 

Damn, I wish I could breathe right now, Senku thought as she noticed the smirk that so often decorated Mozu's face-he was as smug as he was arrogant, although he had been a lot better behaved on the ship after Hyouga revived him than he had been when she had met him on Treasure Island. Since then, she noticed that his main hobby, other than fighting, was following Kohaku around and trying his best to get a rise out of her-Senku had known people in the past who had a relationship like that, but since Senku had never really been all that social back in the modern world, she had never really bothered paying attention to the particular ins and outs of human social interaction. 

"It's okay, you can tell me the truth-I missed you too." 

"Tell me, Mozu-what am I going to do with you?" Kohaku remarked, still squeezing Senku far more tightly than Senku ever wanted to be squeezed by anyone or anything, the expression on her face and her tone of voice all giving away exactly how much Mozu got under her skin as clear as day. 

I know what I'd like you to do, Senku thought, struggling to move-I'd like you to put me down-Kohaku was a great person in a lot of ways, but once someone got her going, she might as well have had a one-track mind, unable to focus on (or remember) anything else until she got her feathers smoothed out again, so to speak. Boy, it sure would be nice to be able to move...Senku's thoughts happened to start wandering just as Kohaku laid into Mozu and Mozu flashed her a grin that was equal parts smug and lewd, which happened to suit him perfectly-some people really wore their personalities on their faces, Senku mused as Kohaku shook her around like a rag-doll, forgetting that she was even holding her in the first place. 

"Kohaku..." Senku finally managed to choke out. 

"What the-oh, there you are, I thought I lost you!" Kohaku shouted after she finally realized she had been holding Senku the entire time. 

"I miss being able to breathe-" 

Mozu, who seemed more amused than ever, gave them both a look that made a curious chill shoot up Senku's spine as Kohaku gently placed her on her feet, Senku taking advantage of the moment to suck in the largest breath she could manage. "Oh, that's right, I forgot about you-" Mozu started, scanning Senku's body more closely than before, his eyes traveling from her feet, up her smooth, slender legs, the curves of her waist and stomach, settling on her small, perky breasts for a moment or two longer before stopping at her face. "Or I should say, I almost forgot you were here right now-I haven't forgotten about you by any means. It's been a while, hasn't it, Senku-chan?" 

Unlike Kohaku, Senku hadn't seen much of Mozu since Hyouga revived him, the two of them hardly speaking until just now. In all honesty, Senku wondered why Hyouga felt inclined to revive him, but she supposed there were worse people he could have chosen to revive all the same. "It has. " 

"Don't worry, he might be a dim-witted pervert but he doesn't bite." Kohaku playfully reassured Senku.

"She just says that because she isn't ready to admit her true feelings." Mozu chimed in. 

"Mozu, how many loose rocks do you have banging around your head right now? You should really get that checked out if we ever revive a doctor." Kohaku shot back, Senku finding the prospect of curling up behind the large rock and falling asleep while the two of them had their little back and forth with each other more and more tempting with each passing second as their conversation grew less and less intellectually stimulating as time passed. She hardly noticed any of what they were going on about, in fact, at least until Mozu was in her personal space all of a sudden-very into it, in fact-so close that she could smell the ocean on his sun-kissed skin and feel his body heat as he held her face, tilting her chin up with his hand. 

His mouth was moving and words were coming out, but for some reason, Senku couldn't focus-she wondered if this was how Kohaku felt too-had she not been paralyzed by some strange, foreign emotion she couldn't name, she might have asked her, but for some reason the words swirling around in her brain all died before they could reach her mouth and pass through her lips. What a bizarre, puzzling phenomenon-it was like nothing Senku could recall feeling, and she wasn't sure if it scared her or intrigued her. 

"It's not everyday I get to spend the evening with a cute girl, let alone two cute girls." Mozu drawled, his voice carefree and relaxed as ever even with the obvious lust in his eyes revealing his feelings as clear as water on a calm lake for all to see. "Of course, there's not really much to do around here, so allow me to offer a suggestion." 

"Oh, really? Like what?" Kohaku added-Senku could detect a little bit of snark in her voice, but also a bit of curiosity-Senku wasn't very interested in sex or romance or anything like that, preferring to enjoy spending time with her friends and working on her different scientific projects and experiments, but she couldn't help but sympathize with Kohaku. Aside from Taiju and Yuzuriha, Kohaku was someone Senku trusted more than anyone else in the world and if Kohaku was happy, then Senku was happy too. To that end, Senku couldn't help but admit she wanted to stick around to see what would happen next even as Mozu removed his hand from her face and idly brushed a strand of white and green hair away from her face. 

"I think you two already know the answer to that. It's a quiet night and I've got a tent all to myself with plenty of room for the three of us, why don't we head back to camp and spend the rest of the night together?" 

Senku looked at Kohaku and Kohaku looked at Senku-the look they shared would later go down in Senku's memory as the moment where all logic and common sense made an abrupt escape from reality for a single night, with Senku unable to remember how or why it happened, only that it happened and that was all there was in the way of an explanation she could ever manage to discover. 

____

Senku was by and far one of the most intelligent people in the world, able to solve almost any problem with sheer brainpower and determination, but as she was lying on a pile of furs and blankets in Mozu's tent, with the tall, athletic man kneeling down to stroke her face after stripping off his clothes without a care in the world, Senku found herself at a complete loss for what to do. Mozu had a rather handsome face, with warm, bright eyes, high cheekbones, and a strong jaw, all accentuating the sharp angles of his masculine features perfectly, yet even so, Senku couldn't rightfully say he was her type because in all her life, she never had a type-all of this was a mystery to her. Every bit of it, what to do, how to seduce someone, how to keep them interested, how to please them-all of it was beyond Senku's range of knowledge and she felt lost, lost in a sea with no shore in sight, as lost as the last star struggling to shine in a galaxy that had long since gone dark. 

"Why don't you two sit on my lap?" Mozu asked, sitting in front of Senku with a carefree expression on his face as he eyed Senku, who was right in front of him, and Kohaku, who was sitting on the edge of the bed taking off her shoes, with equal enthusiasm. 

For someone who had killed scores of people and animals with nothing but a spear or his bare hands, Mozu's touch was surprisingly gentle, nothing at all like what she expected, the prospect almost making Senku feel uneasy at first, at least until Kohaku squeezed her hand, settling down next to her on the soft layer of blankets underneath them after taking off her shoes and placing them in the corner. Mozu seemed equally interested in them both, the look in his eyes suggesting a genuine difficulty deciding which of them he wanted to start things off with. 

"I have an idea." Kohaku chimed in before Senku could be overwhelmed by her inability to figure out how to respond and what to do. 

"What are you doing?" Senku asked as Kohaku pulled Senku close to her, draping Senku's leg over her own, stroking the smaller girl's thigh before looking up at Mozu. 

"Don't worry, just take my lead-men love this kind of thing." Kohaku replied, sliding her hand up Senku's dress. "Since we're here together, we'll start out by putting on a little show for him-" Kohaku turned to look up at Mozu, who seemed as content as anyone inside a tent in the middle of the wilderness could be. "Besides, you could stand to learn some patience, after all. Senku's a virgin, after all, so I can't have you scaring her off by rushing things, after all." 

Senku swallowed hard, deciding to trust Kohaku's judgment as Mozu lied back, reclining in a relaxed position as Kohaku pressed a small kiss to Senku's lips-Senku had never kissed anyone before, and thus had no frame of reference for what a kiss was supposed to feel like, so she decided it felt alright, if not spectacular, and wrapped her arms around Kohaku the same way Kohaku did to her, closing her eyes for a moment when she heard Mozu hum in appreciation. With the way Kohaku was holding her, it almost felt like they were hugging, which Senku liked. Senku was never very touchy-feely, but sometimes when Taiju or Yuzuriha hugged her, it made her feel calm, and Senku felt a pleasant sensation of calm wash over her as Kohaku held her close. When Kohaku broke the kiss, Senku opened her eyes, feeling her face heat up when she noticed the look on Mozu's face-she had seen that kind of look before on a man's face, certainly, but it felt so much more personal now, she thought, her pale face flushing beet red as Kohaku undid the clasps of her dress. Senku supposed it would be helpful to reciprocate, so she helped Kohaku get out of her dress, her small hands fumbling awkwardly as she untied the piece of rope around Kohaku's dress, both of them undressing each other in a few second's time, which Mozu found quite a lovely sight indeed. 

"It's kind of cool in here." Senku replied, wrapping her arms around herself as Kohaku tossed her dress to the side, Senku's nipples hardening a little thanks to the slightly too cold air. For a moment, Senku wondered if Mozu would lose interest once he noticed how small her breasts were, but he didn't seem put off in the slightest when he got a good eyeful of her chest, flashing them both a grin as he pulled them both onto his lap. 

"Well, you don't have a lot of meat on your bones, so that's not a surprise." Kohaku replied, Senku feeling a twinge of jealously even as she admired how pretty Kohaku was-of the two of them, Senku decided that the only feature of hers she liked better than Kohaku's was her hair-Senku had always liked the color of her hair-bright, shining white with green tips, as white and green were her favorite colors. Otherwise, Senku believed Kohaku was by far prettier than she was, not that Mozu seemed to care either way. "But there's nothing wrong with being tiny-at least your boobs won't sag when you get old." 

Now there's a lovely thought, Senku thought sarcastically, regretting Kohaku giving her that mental image, even as Mozu held them closer, resting one hand on Senku's back and the other on Kohaku's. "Trust me, you won't have to worry about that for very long." Mozu commented, reaching down to squeeze Senku's ass a little. There wasn't much to squeeze, but he seemed to enjoy it anyways, causing Senku to squeak a little in surprise, her heart pounding as she feels his hand grasp down hard on her not so round ass. 

"Not that I don't enjoy the lovely sound of your voice, but I think it'd be fun to have you use your mouth to do something else." 

Kohaku shrugged, getting on her knees after Mozu gently moved them off his lap. "Have you ever done this before?" Senku asked her. "I have no idea what to do." 

"Don't worry, it's not complicated-all you have to do is make sure you don't use your teeth." Mozu answered, petting Senku's hair with a filthy grin on his face. 

"It's easier if we both do it at the same time." Kohaku helpfully offered, patting Senku's shoulder as Senku got down next to her. "It's really not that bad once you learn how to breathe, just remember, it's not a race-don't rush it and you'll be fine." 

If you say so, Senku thought as they both started, Kohaku brushing some of Senku's hair away from her face in an attempt to make her more comfortable. It was odd, very odd, Senku thought-nothing at all like what she expected, Senku cautiously swirling her tongue around slowly-maybe a bit too slowly, but she was still kind of nervous, as Kohaku's lips brushed against her, Kohaku pressing her hand on her back when Senku's eyes widened a little, unused to the smell, taste, and everything, really, her thoughts swimming around in her mind in all sorts of directions as she got used to the feeling of something long and hot and thick in her mouth, finding that against all her expectations, the longer she did it, the more and more she noticed the wetness between her legs gathering, slowly warming like something being gently heated by an invisible fire. 

A low groan from Mozu suddenly jolted Senku back into reality, reminding her what she was doing and also of how wet she was now-this is really something else, Senku thought, a little scared but also increasingly aroused as Mozu gripped a chunk of her hair, hissing when Senku and Kohaku swirled their tongues around at the exact same time, their lips brushing together as they did so, both of them working him for a good few minutes until at last Senku felt something hot and slightly salty hit her tongue and she withdrew with a jolt, unprepared for the bizarre intensity of the sensation. 

"I'm sorry, that was probably awful." Senku apologized as Kohaku tossed her something to wipe her mouth with even as Mozu pet her head. 

"Hardly, you're quite good at using that mouth of yours, in fact." Mozu replied, holding her face again for a moment before pressing the pad of his thumb on her tongue. "If I had known, I would have asked to play with you a lot sooner." 

At any rate, Mozu's idea of a reward was something Senku couldn't have dreamed up in ten billion years, completely unprepared for the feeling of his hot tongue inside her pussy after he told her to lie down next to Kohaku. Though her friend was lying right next to her, both of them so close they could hold hands, Senku could barely remember her own name, much less where she was and who she was with when Mozu ate her out, fingering Kohaku at the same time-Senku had no idea how much time passed or what happened during it, being too lost in some strange place in her mind she had never known to exist before, somewhere where nothing and everything seemed real at the same time, slapping her hand over her mouth out of nothing more than pure instinct as she felt his tongue slide over her clit, swirling around it in a pattern that would have driven her out of her mind if she had remembered how to think anymore. There were no thoughts then, however, no questions, concerns, opinions-nothing but the strange white-hot heat gathering inside her like a bomb ready to explode until it finally did and Senku opened her eyes, finding herself safe and secure in Kohaku's arms, both of them sharing a kiss as Mozu was busy for a few seconds deciding which one of them to fuck first. 

Senku could practically hear her heart sing in her ears when Mozu, after spreading her legs apart more gently than she expected him to, guided his cock inside her, pausing a moment after pushing in partway before pushing it in all the way, swallowing hard when he felt how tight she was once he was all the way inside her. 

"How does it feel?" Senku had no idea how to answer, but felt it wise to make an attempt regardless. 

"Big-" she searched her mind for something more eloquent and quickly found nothing. "-and hot. I guess. 

Mozu had to put in a rather impressive amount of effort not to just plow into her with abandon-Senku was far too small for that, as lovely as she was. "Fair enough." he replied. "Kohaku here told me you're a virgin, right?" he asked a rhetorical question, as Senku knew he remembered. "Once I'm done with you, I promise you won't miss it. 

Senku had no response, finding herself feeling even less talkative than usual when Mozu was fucking her, holding her down with one hand while he shoved a few fingers from his free hand into Kohaku's mouth, Kohaku sucking on them with a teasing look in her eyes. Senku was such a tiny little thing, Mozu thought, he had to be careful, but the noises she made when he increased the pace a little were just too lovely to ignore, the blood rushing through his veins so loud he could hear it ringing in his ears with each thrust he gave and each small noise she made, her red eyes welling with tears. Mozu never took Senku for the emotional type, so he found it rather diverting, though he knew at least part of it was because she wasn't used to this sort of thing at all. He could very well lose control inside her if he went on for more than a few minutes like this, he thought, but with Senku's stamina being what it was, it was no surprise to him when such an outcome never happened. 

It was all but impossible not to cry out when Mozu brought Senku to the second orgasm she would have that night, Senku finishing before Mozu could even get all that close-he was still hard, and painfully so, when Senku lost what little strength she had been using to grab one of his arms, flopping back down flat on her back so quickly even Mozu found himself unable to react for a moment. No matter, though, he thought as an exhausted Senku clung onto Kohaku's arm as Mozu decided to give her the same treatment he gave Senku. Unlike Senku, Kohaku wasn't so easy to break, Mozu flashing her a grin as she wrapped her legs around his waist and he felt his mouth go dry as he pushed inside her, much harder than he did with Senku for obvious reasons, a low moan passing his lips as Kohaku and Senku look up at him, Senku swallowing hard as she feels some of her stamina return-she was still tired, a little sore, and more than a little sweaty, but something made her cling onto Kohaku's arm as Mozu fucked her friend, Senku's thighs still aching with the remembered feel of Mozu doing to her what he was now doing to Kohaku. 

Senku envied Kohaku in some ways, especially now, as Kohaku had more strength, stamina, and flexibility, but Senku was also grateful in many ways, especially now, as she felt how nice and warm it felt when she rested her head on the pillow, her head resting in the crook of Kohaku's neck as Mozu thrust again and again, Senku's vision hazy and her mind swimming in some vast, enormous sea that seemed to go on forever with no land in sight. Had Senku possessed the energy to spare, she might have reached between her legs and touched herself, but Senku was far too lazy and comfortable to move even an inch, content to lie right where she was, not wanting to bother wasting energy she didn't have to say or do anything except enjoy how warm and comfortable she felt as Mozu fucked her friend, Senku noticing nothing else except maybe how heavy her eyelids felt when she tried to blink-though she wasn't aware of it, when Mozu got close, she stopped blinking, her eyes staying open so long that if she kept them open a moment longer, it would have started to hurt-it was only when she felt something hot and sticky coat her chest and stomach that Senku realized what she had been doing- 

"Hey, Senku, you got something on your-" Kohaku made a gesture and when Senku looked down after grabbing a towel Kohaku handed her, she noticed exactly what she was talking about. "Oh, gross." Senku thought as her mind started making its journey back to reality, where things made some sort of sense at least some of the time. "Ah, well, it could be worse." 

Before Senku could do anything else, she felt Mozu pull her close, Senku noticing quite suddenly how warm his chest wasy-firm yet soft at the same time, the soothing sound of his hearbeat filling her ears as Kohaku curled up next to her, the three of them bothering with nothing else besides draping a thin blanket over themselves as they all settled in and got comfortable. Not in ten billion years did Senku ever imagine she would end up being turned into a statue, revive thousands of years in the future, and embark on a journey to re-created modern civilization, let alone do so by traveling halfway around the world and following that up by losing her virginity to a man and a woman at the same time, with one of them being one of her best friends, no less. Life really made no sense sometimes, Senku thought, and logic seemed about as relevant to what actually happened as magic, but maybe life not making sense wasn't always such a bad thing, Senku decided as she passed out in Kohaku and Mozu's arms, the moon high in the sky and the stars lighting up the night sky like the world's most beautiful painting. If the rest of her time in America would be even half as interesting, Senku thought, her journey would prove to be more than worth it. 

**Author's Note:**

> Remember, kids, the pullout method is only a valid form of birth control in a stone age world where there are no condoms of birth control-stay in school, don't do hard drugs, blah blah blah.


End file.
